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Physics Final 2010
Know:
Opposite charges attract
When you give something an electric charge,
Electrons are moving from one thing to another
The Force between electric charges depends on
the square of the distance
An electron has a charge of -1.6 x 10-19 C.
If an object has a charge of 8 x 10-19 C, describe what
causes the charge
Know Units:
C
A
V
coulombs charge
amperes current
voltage
potential difference
J
joules
All energy
W
ohms
resistance
Definition of potential difference, resistance,
and current
Ohm’s Law V=IR
What things change the resistance of
a wire, and how
For resistors in series and parallel,
know what stays the same across all,
and what is the sum
Calculate equivalent resistance
?10 W
?5 W
V
I 4 A
? A
R
? W
10
eq. res.
4W
12 W
24 V
6W
A
Equivalent Resistance? 24 W
2W
Voltage in 6 W resistor? V = IR = 6V
Current in circuit? 1 A
Current in 6 W resistor? 1 A
Power dissipated by 6 W resistor?
P = IDV = 6 W
Magnetic field lines go from the north pole to
the south pole
Right hand rules
Waves are the transfer of energy
Definitions:
wavelength
frequency
period
amplitude
period?
frequency?
period = 1/frequency
velocity maximum?
restoring force maximum?
acceleration maximum?
For a pendulum:
l
T  2
period
g
length
gravitational
acceleration
If you increase l, what happens to T?
If you decrease g, what happens to T?
10 m
2m
f = 4 Hz
l?5m
amplitude? 2 m
wave speed? v = f l = 20 m/s
Transverse Wave
wavelength?
frequency?
amplitude?
Longitudinal Wave
wavelength?
frequency?
amplitude?
Sound
Longitudinal Wave
Needs a medium to travel through
Pitch is how high or low a sound sounds
Pitch is a measure of frequency
The Doppler Effect
Mirrors and Lenses
Images are described in terms of:
real or virtual
upright or inverted
magnification
Light is an inverse square function
Plane Mirrors
image is virtual, upright, magnification = 1
object distance = image distance
angle of incidence = angle of reflection
Concave Mirrors
between
C
andinverted,
f…real,
inverted,
outside
at C…real,
inside
f…virtual,
C….real,
inverted,
upright,
mag
=bigger
smaller
1 bigger
C
f
Convex Mirrors
Always form virtual, upright, smaller images
Concave Lenses
f
f
Index of Refraction
n…a ratio of the speed of light in a vacuum
with the speed of light in a material
Know how light bends when it goes from
one “n” to another